81. Pipe A can fill an empty tank in 45 minutes and pipe B can empty it in one hour. If pipe A is [ ] opened at 10:00 AM and pipe B at 10:15 AM, by what time does the tank get filled? \( \begin{array}{lllll}\text { (a) } 12: 00 \mathrm{PM} & \text { (b) } 12: 15 \mathrm{PM} & \text { (c) } 12: 30 \mathrm{PM} & \text { (d) } 1: 00 \mathrm{PM} & \text { (e) } 1: 30 \mathrm{PM}\end{array} \)

Is the number 14 a prime number? Explain why or why not.

11) \( 120 \% \) of 18 is what? \( \begin{array}{ll}\text { 13) What is } 270 \% \text { of } 60 ? & \text { 12) } 25 \text { is what percent of } 37 ? \\ \text { 15) } 37 \% \text { of } 41 \text { is what? } & \text { 16) } 9 \text { is what percent of } 84 \text { ? } \\ \text { 17) What percent of } 88.6 \text { is } 70 ? & \text { 18) What percent of } 137 \text { is } 86 ?\end{array} \)

23. Raúl gana \( \$ 1800 \) pesos a la semana, pero paga \( \frac{2}{5} \) de su sueldo para su viaje de graduo- ción; ¿cuánto dinero representa la fracción?

If \( 3^2 \) is calculated, what is the result?

The population of a place in a particular year increased by \( 15 \% \). Nexty cal, net increase or decrease percent in the intial population. ₹ 648 is divided into three fricuds Raghav, Anil and Sobha. Anil gets \( \frac{4}{5} \) of amount that Raghav gets and Sobha got \( 75 \% \) of amount that Anil got. How much money did each one of them got?